


The Pink Liquid

by SpookySusie



Category: Undertale (Video Game)
Genre: Alphyne, Alphynecentric, Angst, Determination (Undertale), F/F, First Kiss, Heavy Angst, Mad Scientists, Science Experiments, alphys tries to fix everything, emphasis on tries
Language: English
Status: Completed
Published: 2018-12-03
Updated: 2018-12-03
Packaged: 2019-09-06 04:32:54
Rating: Mature
Warnings: Graphic Depictions Of Violence, Major Character Death
Chapters: 1
Words: 2,874
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/16825207
Author URL: https://archiveofourown.org/users/SpookySusie/pseuds/SpookySusie
Summary: After Chara enters the Underground and kills those she loves, Alphys uses a last-ditch effort to save her people, one that she promised she would never use again…November's Patreon poll results.





	The Pink Liquid

**Author's Note:**

> This was...torturous to write. And there'll be more later this month! Don't worry, this isn't the only chapter!
> 
> I'm having a commission sale that's Deltarune/Undertale-centric! [More info here!](https://shutendoujiwriting.carrd.co/#sale) [Email to get a spot!](mailto:shutendoujiwriting@gmail.com)
> 
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Chara knew about the cameras, and Alphys could tell. Even from the first camera, hiding in the bushes before San’s first sentry station, the child gave the camera a dust-covered wave and a creepy smile.

_ Something’s wrong. _

Alphys took a few breaths, and called her friend.

_ I don’t want to do this. I said I’d never do this again. _

Undyne picked up on the first ring. “Hey, Al. What’s going on?”

“The last human showed up.” Alphys rocked back and forth in her chair to keep herself from stuttering.

“Yeah, I heard from Papyrus. He’s pretty excited!”

“Yeah, well, about that…”

Undyne paused for a bit as Alphys’ voice trailed off. “Is there something...wrong?”

“Just. Get down here okay? Like, as soon as possible?”

Undyne didn’t even bother leaving a goodbye message. She hung up immediately.

_ Great. Guess I can’t prolong the inevitable. _

Alphys dug around her desk for a moment, stopping to only look at her console, with the child’s wicked-looking smile as they stuck a plastic toy knife into one of the dog guards. The dog yelped and howled, thrashing in pain as more bullets collected to harm their attacker, but to no avail.

Alphys swallowed her stomach acid and finished writing her note.

_ Y’know what I pretend is the bathroom? I’m in there. Go to the third floor down. I’ll be waiting. _

“That sounds really cryptic, you idiot,” Alphys groaned, hitting her head on the desk. “But I guess it can’t be helped. It’s not like it matters anymore.”

Instead of crumpling the note as she normally did and trying again, she left it outside the True Lab, just as she heard the front door opening.

_ Shit. She’s fast. She’s already here. And I’m not ready… _

_ Stop panicking, Alphys. It’s okay. It’s just Undyne. _

_ For now. _

As Alphys, blinking back tears, heard Undyne go, “What the fuck?” and the rustling of paper.

_ I wonder if she can even read my handwriting. _

“Alphys?” she heard Undyne call from the door of the True Lab.

Alphys didn’t reply. She couldn’t.  _ Gotta save my voice for a little longer. _ And she made her way down the elevator.

Where  _ it _ still stood.

_ It _ haunted her. Every day, every night.  _ It _ stood there, mocking her daily when she fed the Amalgamates, like a sinister Plague Doctor’s mask she had seen from the shows from the Surface.

“ALPHY?”

Alphys heard footsteps behind her, quick enough to definitely be Undyne’s. 

“I’m--”

She never finished her sentence before Undyne whisked her off her feet in an aggressive embrace. Alphys hugged her back for a moment, just long enough to memorize how Undyne’s arms felt holding her.

_ It would be the last time, after all _ .

“Are you okay?” Undyne set the scientist down and looked around. “The fuck is this place?”

“The True Lab,” Alphys said, her voice small. “Did you...see anything else on your way down?”

Undyne frowned. “I saw your console, and that kid…”

Alphys exhaled slowly. She’d rather have Undyne know the current stakes than her secrets.

_ I can die with what I did. What this Lab is really for. _

“Undyne, do you mind...having a seat?”

Undyne looked around some more, turning her entire body. “Bitch, where?” she asked with a sharp laugh.

It took all of Alphys’ willpower not to cry. She knew, deep within her Soul, that it’d be the last time she ever heard Undyne laugh. “In the, um. That.” She pointed toward  _ it _ .

_ It _ served a dual purpose, extracting Determination from subjects as well as inserting it. Alphys had ran several other experiments with inserting Determination, sure, including giving it to Undyne in microdoses as a small treat (she claimed it tasted good), but this was the most direct way. The most powerful way.

_ The only way to save the Underground _ .

“Um. Okay. I trust you.” And she sat.

_ Please don’t trust me. I’m not meant to be trusted. I’m not worthy. _

“So, uh...what is this thing?”

“D-do you remember our, um. First...date?”  _ Goddammit, Alphys. Not a date. _ “I-I mean! Not a  _ date _ date, but when we first started hanging out? And I gave you that, uh...that drink! When I got ice cream and you said--”

“The pink drink?” Undyne had a slightly playful smile on, her grin growing wider with every time Alphys stumbled over her words. 

“Y-yeah, that. Well, I wasn’t really...forthcoming with what it was.”

“True.” Undyne grinned. “You didn’t say what it was at all. You said, ‘Hey, wanna try this?’ and I said ‘Well shit, sure, as long as it’s not cold.’ I remember feeling weirdly strong afterward.” Undyne’s smile fell. “What was it?”

“I don’t know what it’s  _ actually _ called,” Alphys admitted, beginning to pace a bit. “But I call it Determination. It’s something that’s...ingrained in human Souls, that we monsters don’t develop on our own. It’s how...that child is so able to k-kill everyone.”

Undyne blinked a few times. “So you gave it to me like food?”

“I mean! You’re really tough, a-and it was only a microdose, so it wouldn’t’ve done any real harm! It’s in the larger doses where it’s lethal. Worst case scenario, you would’ve gotten a bit sick, but best case scenario--”

“I’d be stronger,” Undyne finished for her. Her eyes narrowed slightly. “What, was I just a test subject to you? A friend you made so you could create a killing machine!”

“N-no! Of course not! I just…” Alphys looked at the ground, forever stained with a vague shade of pink, rejected from all the monsters she had experimented on in the past. “Asgore said you were the only monster who could harness Determination. When he found out we became...friends...he told me to try. So I did.”

Undyne was quiet for a bit, still taking in the machinery around her. “Okay. So...what do I do?”

“That’s it? You don’t have any questions?”

Undyne crossed her arms. “I do have a  _ lot _ of questions, such as, ‘What am I doing here?’ and ‘What are you going to do with me?’ and ‘How do we stop this child?’”

Alphys’ phone beeped then, and she pulled it out of her labcoat.

Sans.

_ The child has my brother. He’s mostly dust now. You know what to do. _

Alphys trembled and handed the phone to Undyne, standing on her toes to reach her in the machine. 

Undyne’s eye scanned the words before she covered her mouth. “Papyrus…”

“This child is...really going to eradicate all of us. And inserting this much Determination, even if you’re the only one of us who can handle it, might kill you, but...you’re our only hope. We need you to be strong enough to defeat this level of Determination.”

Undyne inhaled sharply, then exhaled slowly. Through her only eye, it was visible to Alphys how quickly her mind was working. “I’ve come to terms with death a long time ago. It’s kinda...well, it goes hand-in-hand with what I do. I’m okay with dying. But I won’t if I can help it.” She grinned--or was it a grimace? “And I’m pretty damn sure I can help it. So fuck me up with Determination, Doc.”

“I was...afraid you’d say that.” Alphys opened up the cabinets, putting together a few bags of saline--ones she had made specifically for Undyne, knowing she’d need more water than the average subject.

“What’s that?” Undyne asked.

“An IV. Just to...keep you hydrated.” Alphys wiped down Undyne’s arm, feeling around for her veins before inserting it. She then hooked the IV to the IV pole. “I’ll...I’m gonna get the rest of my supplies. I’m gonna drip the Determination through the IV instead of inserting it directly. It’s...not something I’ve tried yet, honestly, but I feel like it’ll work out better.”

Undyne quirked an eyebrow. “Better than what?”

Alphys left wordlessly, realizing what she almost said.  _ We’re gonna die together, and I’m gonna die with my secrets. _

In one of the adjacent rooms was where Alphys kept the rest of the Determination she harvested. Sometimes, she took little bits for those “pink drinks” Undyne liked, but this time, she took an entire, unopened bottle, and a syringe to insert into the IV bag. 

“That’s not even that much,” Undyne commented upon seeing the pink liquid. 

“I...diluted it before. This has never been opened. I’ve been keeping this f-for--”

“Did you know that this would happen?” Undyne asked as Alphys opened the syringe from its sterile packaging. 

“N-no, not exactly. I just wanted to be prepared for the worst.” Alphys withdrew the pink liquid from its vial. “People always said that the last person would be the Angel of Life or Death, and if we were prepared for Death, then maybe...maybe we’d stand a chance.”

Undyne leaned back, bracing herself for the impact of the Determination. “I see I’ve taught you well.”

Alphys emitted a nervous giggle. “Y-yeah, I guess so.” Alphys readied the syringe to the bag. “I’m gonna...start inserting it, okay?”

“Should I hold onto something?” 

Alphys blinked. She wasn’t equipped for that. “Um! You can! Hold my hand, if you’d like!”

Undyne grinned, though her eye was sad. “I’d like that.”

So squeezing Undyne’s hand with one and using the syringe with another, Alphys emptied the pink liquid into the bag.

At first, nothing happened. 

Alphys rubbed Undyne’s hand in preparation for what was to come, not dropping her gaze from her friend.

“Before it begins, I…”

Undyne quirked an eyebrow but waited patiently.

_ Just ruin the moment before you kill her, Alphys. _

“We m-may not make it, so...I just wanted to say that…”

Alphys didn’t get to finish, for Undyne promptly passed out.

“Shit!” Alphys let go of her hand and adjusted Undyne’s unconscious body to stay in the machine. The IV had turned from a pale, pastel pink to the color of Pepto-Bismol, and was now sliding into her body. Undyne twitched a few times before lapsing into a full seizure.

_ It’s failing. I’m failing. Asgore was wrong. Undyne can’t handle this. _

_ But I can hope. _

So she held onto her, keeping her from falling out, tears streaming down her face as she convulsed. It lasted for only a few minutes, but to Alphys, it felt like hours before Undyne eventually vomited pink and went limp. 

_ Now’s the real test _ .

Slowly, the bag drained until there was nothing left, and Alphys traded it out for pure saline. She pulled up a chair and held onto Undyne’s cold, limp hand with both hands. Was it Alphys’ imagination, or was it beginning to feel slimy?

_ You’ve failed. You’re a failure. A fraud. Why did you think you could save everyone when you couldn’t even save one person? _

But her thoughts were proven wrong.

Undyne opened her eye.

And it felt...different somehow. Not necessarily in a bad way, no, but as though it was the first time someone stared at her with such scrutiny.

“A-are you okay?”

Undyne didn’t say anything.

_ Fuck, Alphys.  _ “D-do you know where you are?”  _ A simple cognitive test will prove that you’re a colossal failure, just so you can have that closure before you die. _

“Your lab.”

“Do you re-remember who I am?”

Undyne’s gaze softened. “Dr. Alphys. My best friend.”

Alphys’ heart hammered in her chest. “Your name?”

“Undyne.”

“The year?”

Undyne told the correct year.

“And what’s currently happening?”

Undyne dropped her gaze. “The world is dying.”

“Good. I mean! Not good about the dying part, but...that was...the correct answer.” Alphys cleared her throat, anxiety clogging her ability to form coherent sentences. “I-I’m gonna do a few reflex tests. You just had a seizure from the Determination, s-so I wanna make sure everything’s okay.”

As Alphys checked the dilation of Undyne’s pupils and her reactions to stimuli, Undyne said, “You’re really good at this, aren’t you.”

Alphys felt herself turn almost as pink as Determination itself. “I!”

Undyne sighed. “It’s a shame that I’m about to go into battle without ever...knowing a future with you.”

Alphys made a vague squeaking noise. “F-future?”

“Well, yeah.” Undyne smirked, then winced as Alphys pulled out the now-empty IV. “Although...with your help, we could survive.”

Alphys nodded. “Yes. That’s...what I’m trying for, anyway.”

“Not could.” Undyne said up. “Would. We  _ will _ survive this.”

It was hard not to smile. The Determination shined within Undyne, giving her entire body a glow. Asgore was right; Undyne was fully capable of harnessing Determination.

It was as though she  _ was _ Determination Itself, the embodiment of the power that would keep Monsterkind living. The power that would stop the Angel of Death. 

Undyne slid out from  _ it _ and approached Alphys, crouching to the scientist’s level. “It’s because of you that we’re gonna survive. Don’t be talking down to yourself so much.” Undyne tilted her head, the light catching beneath whatever was now in her empty eye socket. Alphys always did appreciate that Undyne bared her scars to her, a sign of intimacy no one had ever showed her before.

“But before I go.”

Alphys’ eyes widened as Undyne’s face got closer to hers. “Just in the offchance that I’m not more determined than this human...I love you.”

“I?” Alphys blinked.

“It’s okay if you...don’t feel the same. I just wanted to say this.” She held both of her hands and gave them a squeeze, her hands somehow both slimy and sticky. “I’ll be fighting for a future for us, for the other generations, and for a life outside of here. And we’ll shatter the barrier with this human’s rotten soul.”

Alphys wasn’t sure what to say. Part of her wanted to leap into Undyne’s arms and scream and holler about how much she did  _ indeed _ feel the same way, but something made her feel cemented on the spot, rooted into the tile floor of the True Lab. Her heart pounded in every inch of her skin, generating body heat she didn’t know she was capable of.

“What is it?” Undyne asked.

“I…” Alphys looked at the tile. “I love you, too. I always have. It was...so hard to put you through so much pain. And there’s so much we need to talk about after all this, so much we need to share with one another, that I just--”

“Alphys.”

“What?”

“Shh.”

And then it happened. The moment of Alphys’ dreams, the moment she never thought would happen. 

Alphys had  _ thought _ about kissing Undyne almost daily...well, honestly, more than that; any waking moment she had where she was near Undyne, anytime she wrote coding variables with her name in it, every time there was a kissing scene in Mew Mew Kissy Cutie (and there were  _ a lot  _ of kissing scenes). She wasn’t sure how it would be at first; it wasn’t like there were a lot of monsters out there who wanted to kiss Reclusive Nerd Dr. Alphys, and Undyne’s teeth looked as though they would pose some issues. 

Yet somehow, they didn’t. It was soft, her teeth not even scraping her. It also was not as agonizingly long as many of the kisses Alphys had seen in the past, but as brief as it needed to be, yet sent her head spinning for what felt like decades. 

“I!” Alphys said finally.

“I’ll be back, Doc,” Undyne said, her voice low, almost husky in a way Alphys had never heard before. Then Undyne pulled away, looking confused. “Um. Actually, can you show me the way out?”

“S-sure, Undyne!” Alphys took Undyne’s hand and led her to the elevator. “Please just...when you’re out there...be careful, okay?”

“I’m always careful.”

Alphys laughed. “You’re  _ never _ careful. You’ve burnt your house down three times.”

“It’s called  _ efficiency,  _ Alphys! If I bake cookies for ten minutes at four hundred degrees, then I can bake them for  _ one _ minute at four  _ thousand _ degrees!”

“That’s not how baking works...wait, is that why you had me modify your oven?”

Undyne chuckled and patted Alphys’ head, and her heart soured.  _ I was wrong. That wasn’t the last time I heard her laugh _ .

Alphys led Undyne to the front door, dropping her hand. “Um...if it’s not too much to ask…”

“Are you asking me to kiss you again?”

“M-maybe…”

Undyne held Alphys’ face in her hands. “Be direct and I’ll do it.”

In the tiniest voice Alphys had ever heard herself speak in, she said, “Kiss me again, Undyne?”

With a chuckle, Undyne obliged. If the first kiss was gentle, this one was  _ electrifying _ , as though Undyne was transferring every bit of Determination to Alphys herself. Her teeth did manage to brush against her lips, but it wasn’t as weird as Alphys had always wondered if it would be. She either felt that it would’ve been uncomfortably arousing, or just plain uncomfortable, yet...it was only the former, without the discomfort. 

When Undyne pulled away, she said, “We’ll continue when I get back. When I’m done saving the world.”

Alphys leaned against the doorway, keeping it open as Undyne grabbed a cup of water and ran off to her place to get read.

_ I did something right. Now to see how long it lasts. _


End file.
